CVE-2026-41213

medium

Published 2026-04-16 · Modified 2026-06-02

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CVSS v3

5.9

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.9

Description

@node-oauth/oauth2-server is a module for implementing an OAuth2 server in Node.js. The token exchange path accepts RFC7636-invalid code_verifier values (including one-character strings) for S256 PKCE flows. Because short/weak verifiers are accepted and failed verifier attempts do not consume the authorization code, an attacker who intercepts an authorization code can brute-force code_verifier guesses online until token issuance succeeds.

Predictions

Exploit likelihood

69%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Package impact

Ecosystem	Package	Vulnerable	Fixed
npm	@node-oauth/oauth2-server	`<5.3.0`	`5.3.0`

Application impact

Vendor	Product	Versions	Fixed
node-oauth	node-oauth\/oauth2-server	`{"endExcluding":"5.3.0"}`	`5.3.0`

References

CWEs

CWE-307 CWE-1289

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.